A nonvolatile semiconductor storage device is disclosed, for example, in Patent Documents 1 to 4, respectively.
Non-Patent Document 1 discloses a flash EEPROM (Electrically Erasable Programmable Read Only Memory) which improves a writing speed by making a source electrode of a memory cell a negative voltage when writing.
Non-Patent Documents 2 and 3 disclose movement of electrons by a tunneling effect through an insulator film in a programmable flash memory.
Further, Non-Patent Document 4 discloses a programmable flash memory that utilizes a resonant tunneling effect in which a silicon layer is inserted into an oxide film.    [Patent Document 1] Japanese Patent Laid-Open No. 2000-299395    [Patent Document 2] Japanese Patent Publication No. 2005-519472    [Patent Document 3] Japanese Patent Laid-Open No. 2007-5380    [Patent Document 4] Japanese Patent No. 1421951    [Non-Patent Document 1] [VLSI Report] AG-AND-Type Flash EEPROM Cell Writing Time Shortened to 1/20 (http://techon.nikkeibp.co.jp/article/NEWS/20050617/105890/)    [Non-Patent Document 2] “Electron Tunneling Through an Al203 Thin Film on NiAl(110) in Scanning Tunneling Microscopy”, Hiroshi IWASAKI and Koichi SUDOH, Jpn. J. Appl. Phys. Vol. 41 (2002) pp. 7496-7500, Part 1, No. 12, December 2002    [Non-Patent Document 3] “Electron Tunneling through SiO2/Si Structures in Scanning Tunneling Microscopy”, Hiroshi IWASAKI, Masahide GOTOH and Koichi SUDOH, Jpn. J. Appl. Phys. Vol. 40 (2001) pp. 5116-5120, Part 1, No. 8, August 2001    [Non-Patent Document 4] “Robust Multi-bit Programmable Flash Memory Using a Resonant Tunnel Barrier”, Shieun Klm, Seung Jae Baik, Zongliang Huo, Young-Jin Noh, Chulsung Kirm, Jeong Hee Han, In-Seok Yeo, U-In Chung, Joo Tae Moon and Byung-II Ryu, 0-7803-9269-8/05, 2005 IEEE